New chip places qubits with magnets, not random chance

Florida State University researchers are tackling a core challenge in quantum computing: reliably building qubits. The team reports in PRX Quantum a new chip design that uses magnetic levitation to position single electron qubits above a surface of solid neon, moving beyond the random chance that previously dictated qubit performance.

“Instead of hoping that the right nanoscale feature appears in the right place, we want to decide where each electron qubit sits,” said Professor Wei Guo, study co-author and mechanical engineering professor. This approach pairs ultraclean materials with chip-based control, potentially enabling more scalable quantum technologies.

Magnetic Levitation Enables Designed Electron-on-Neon Qubit Placement

A fundamental challenge in building stable qubits has been overcome through the precise placement of single electrons, achieved not by chance, but by magnetic levitation. This approach directly addresses the issue of random defects on traditional solid neon surfaces that previously dictated qubit performance and location. The team’s innovation moves beyond simply depositing neon onto a chip; instead, they propose using magnetically levitated microparticles as clean carriers for individual electrons.

“A simple way to think about it is that we give the electron a tiny, clean, floating island to sit on, rather than asking it to find a good spot on a rough landscape,” explained Yinghe Qi, a postdoctoral researcher at the National High Magnetic Field Laboratory. The chip beneath continues to provide the necessary microwave circuits for qubit control and readout, integrating established technology with this novel positioning method.

This level of control is crucial for scalability, as random surface imperfections have historically limited the reproducibility of electron-on-neon qubits. In this architecture, the qubit is no longer found by chance, but built by design.

The researchers demonstrated that essential components, clean electron confinement, tunable energy levels, and qubit communication, can function cohesively within this design, though a working prototype remains to be built. Yiming Xing, a researcher at the FAMU-FSU College of Engineering, highlighted the core benefit: “The main advantage is reproducibility.” The team anticipates leveraging existing fabrication methods to transition from this theoretical design to a functional device, potentially unlocking more predictable and stable quantum computing architectures.

Superconducting Loops Suspend Neon Microparticles for Improved Qubit Control

Controlling the environment is key to building reliable qubits; current electron-on-neon designs suffer from random imperfections on the neon surface that dictate qubit performance. These uneven bumps trap electrons, meaning the location and quality of a functioning qubit has historically relied on chance. Engineers at the FAMU-FSU College of Engineering are proposing a solution: magnetic levitation to suspend tiny neon microparticles, creating a precisely positioned and exceptionally clean platform for individual electron qubits.

Rather than relying on a solid neon film inheriting imperfections from the underlying substrate, the new chip design utilizes superconducting loops to hold nearly spherical neon microparticles aloft. This levitation technique allows for the creation of a defined space for each electron qubit, eliminating the unpredictable influence of surface defects. This focus on reproducibility represents a shift in electron-on-neon qubit development. While a working prototype remains under development, the compatibility of the superconducting loops, microwave resonators, and patterned chip structures with existing fabrication methods suggests a relatively straightforward path toward realization.